Electronic component module

ABSTRACT

An electronic component module according to the invention includes: a mounting substrate  11  including a shield layer  13  and on which a first cavity  14   a  and a second cavity  14   b  are formed; a first electronic component  16   a  positioned in the first cavity  14   a  and used in a first frequency band; a second electronic component  16   b  positioned in the second cavity  14   b  and used in a second frequency band; lid members  15  which seal the first cavity  14   a  and the second cavity  14   b ; and patch antennas  17  which transmit/receive radio waves in the frequency bands, the antennas connected to the electronic components  16 ; wherein the electronic components  16  are mounted on the mounting substrate  11  via a substrate component  19  having a higher heat resistance than the mounting substrate  11  and that the mounting substrate  11  is composed of a member having a lower dielectric constant that the substrate component  19.

BACKGROUND OF THE INVENTION

The present invention relates to an electronic component module and in particular to an electronic component module on which electronic components operating in a plurality of frequency bands are mounted.

Recently, there is a growing need for a more compact and higher-performance communications system used in the microwave band or millimeter band with easy broadband applicability and higher resolution. As a solution to satisfy such a need and reduce transmission loss between the electronic components of a communications system, there is known a technology which packs high-frequency devices or electronic components such as an amplifier, a mixer, an oscillator and a multiplier into an electronic component module in the form of a package, as mentioned in the Japanese Patent Laid-Open No. 237867/1997.

The Japanese Patent Laid-Open No. 326488/1984 discloses a technology to shield an input/output terminal while keeping out of the way of cable routing in order to avoid the influence of malfunctions caused by an electromagnetic wave in such an electronic component module.

However, the technologies described in these official gazettes require dedicated substrates and cases. Fabricating an electronic component module by using such a substrate and a case requires a complicated manufacturing process and time, thus resulting in higher costs.

Another approach of advancing the feature of the electronic component module which installs electronic components operating in frequency bands different from each other in a single package presents a problem of interference between electronic components operating in frequency bands different from each other according to the aforementioned technology.

In order to suppress propagation loss or improve antenna efficiency, it is preferable to use a member with a low dielectric constant for a mounting substrate on which electronic components are mounted. The problem is that a member with a low dielectric constant is generally made of resin and has low heat resistance. For example, when an electronic component is mounted by way of heat-compression bonding of an Au or Au—Sn alloy which requires heat treatment at some 400 degrees centigrade, the electronic component cannot be mounted on a resin substrate with low heat resistance, so that only limited electronic components can be mounted on such a resin substrate.

SUMMARY OF THE INVENTION

The inventions aims at providing an electronic component module which installs electronic components operating in frequency bands different from each other in a single package while preventing interference.

The invention further aims at providing an electronic component module which suppresses propagation loss and which can mount electronic components requiring heat-compression bonding while improving antenna efficiency.

In order to solve the problems, an electronic component module according to the invention comprises: amounting substrate including a shield layer and transmission lines and on which are formed at least a first cavity and at least a second cavity as partitions; at least a first electronic component positioned in the first cavity and used in a first frequency band; at least a second electronic component positioned in the second cavity and used in a second frequency band; lid members equipped with a shielding feature which seal the first cavity and the second cavity; one or more antennas formed on a surface of the mounting substrate, the surface opposite that on which the first electronic component and the second electronic component are mounted, the one or more antennas transmitting/receiving radio waves in at least any one of the first frequency band and the second frequency band and being connected to the corresponding electronic components; and a plurality of terminals formed on the mounting substrate, the terminals connected to the first electronic component and the second electronic component via the transmission lines; characterized in that at least one of the electronic components is mounted on the mounting substrate via a substrate component having a higher heat resistance than the mounting substrate and that the mounting substrate is composed of a member having a lower dielectric constant than the substrate component.

According to the invention, the first and the second electronic components are installed in electromagnetically shielded cavities different from each other to form a module. As a result, the electronic components are shielded per frequency band thus improving the isolation characteristic. It is thus possible to provide an electronic component module which installs electronic components operating in frequency bands different from each other in a single package while preventing interference.

The electronic components are mounted on a heat-resistant substrate component by way of heat-compression bonding and the substrate component is coupled to a mounting substrate with a low dielectric constant. This provides an electronic component module which can mount electronic components requiring heat-compression bonding while suppressing propagation loss and improving antenna efficiency.

The electronic component module according to a preferred embodiment of the invention is characterized in that the lid members are made of a metal or a nonmetal on which a metallic shield layer is formed.

This makes it possible to provide an electronic component module which installs electronic components operating in frequency bands different from each other in a single package while preventing interference.

The electronic component module according to a preferred embodiment of the invention is characterized in that the mounting substrate is made of resin and that the substrate component is made of ceramic.

This makes it possible to provide an electronic component module which can mount electronic components requiring heat-compression bonding while suppressing propagation loss and improving antenna efficiency.

The electronic component module according to a preferred embodiment of the invention is characterized in that the cavity has a shape which suppresses the unwanted resonance mode in the cavity and the unwanted propagation mode in the cavity in the operating frequency band of the electronic component in the cavity.

This obtains a good performance characteristic.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a sectional view of an electronic component module according to an embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Embodiments of the invention are described below in detail referring to attached drawings. In the attached drawings, same members are assigned a same sign and duplicated description is omitted. The embodiments are particularly useful embodiments of the invention and the invention is by no means limited to the embodiments.

FIG. 1 is a sectional view of an electronic component module according to an embodiment of the invention.

As shown in FIG. 1, the electronic component module 10 according to this embodiment is equipped with a mounting substrate 11 composed of a dielectric whose dielectric constant is about 2 to 4.5 and which is made of resin such as vinyl benzyl. On the mounting substrate 11 are laminated transmission lines 12 and a shield layer 13 used in common with a ground layer. The transmission lines and the shield layer 13 are made of for example Au, Ag, Cu or W. The shield layer 13 may be separate from the ground layer. The mounting substrate 11 may be made of material other than resin but its dielectric constant is desirably as low as possible.

On the mounting substrate 11 are formed an outer wall 11 a and a partition wall 11 b which partitions the area into a plurality of sub-areas. This forms multiple cavities 14 as partitions on the mounting substrate 11.

On the mounting substrate 11 are arranged lid members 15 which seal the cavities 14. The lid members 15 are equipped with a shielding feature, for example by way of metal-plated resin. Both sides of the cavities 14 in the direction of height as well as the shield layer 13 are electromagnetically shielded. Note that the lid members 15 may be made of metal to provide a shielding feature.

A shield layer such as metal plating may be formed on the outer wall 11 a and the partition wall 11 b in order to electromagnetically shield the cavities 14 in all directions.

Or, by forming a through hole or a via hole in the outer wall 11 a or the partition wall 11 b and using the through hole or via hole to electrically connect the lid members 15 and the shield layer 13, the cavities 14 may be electromagnetically shielded in all directions.

In the cavities 14, electronic components 16 as a plurality of high-frequency devices are coupled to the mounting substrate 11 by way of surface mounting with solder or brazing material, or flip-chip mounting with Au or Au—Sn alloy.

These electronic components 16 include a plurality of first electronic components 16 a used in the submillimeter band, for example 25 GHz (first frequency band) and a plurality of second electronic components 16 b used in the microwave band, for example, 5 GHz (second frequency band). The first electronic components 16 a and the second electronic components 16 b are installed in the separate cavities 14. To be more precise, the first electronic components 16 a are installed in the first cavity 14 a while the second electronic components 16 b are installed in the second cavity 14 b.

As mentioned earlier, both cavities 14 a, 14 b are electromagnetically shielded. The first electronic components 16 a and the second electronic components 16 b are installed in the first cavity 14 a and the second cavity 14 b respectively, so that the electronic components 16 a, 16 b are shielded per frequency to prevent interference. This improves the isolation characteristic thereby obtaining a stable performance characteristic.

The first cavity 14 a or the second cavity 14 b may be single or plural. The cavity 14 has a shape of a rectangle when illustrated, but may have various shapes, such as a circle and an ellipse.

The shape of the cavity 14 is preferably formed so that an unwanted propagation mode or an unwanted resonance mode will not take place in the operating frequency band of the electronic component 16 in the cavity 14.

For example, in case the electronic component 16 is a power amplifier, an unwanted propagation mode in the cavity 14 in the operating frequency band of the electronic component 16 forms a transmission line other than the transmission lines 12 in the space. This could degrade the performance of the electronic component module 10, that is, the backward passing characteristic or isolation characteristic of the electronic component 16. In order to solve such a problem, the cavity 14 is preferably formed so that the frequency band in which the cavity 14 can operate as a waveguide when the propagation mode appears in the cavity 14 will be higher than the operating frequency band of the electronic component 16.

An unwanted resonance mode in the cavity 14 in the operating frequency band of the electronic component 16 could degrade the performance of the electronic component module 10, for example, degrade the transmission characteristic of the transmission lines 12. The cavity is preferably formed so that the operating frequency band of the electronic component 16 and the frequency at which an unwanted resonance mode takes place will be different from each other.

The “unwanted propagation mode” refers to the form of electromagnetic field distribution in which the cavity 14 is operable as a waveguide in the operating frequency range of the electronic component 16. The “unwanted resonance mode” refers to the form of electromagnetic field distribution in which the cavity 14 is operable as a waveguide resonator in the operating frequency range of the electronic component 16.

The aforementioned frequencies are exemplary. The invention is not limited to these frequencies as long as the operating frequency bands of the mounted electronic components 16 differ from each other.

While the electronic components 16 operating in two frequency bands are mounted in this embodiment, it is possible to mount electronic components operating in three or more frequency bands. In this case, the electronic components operating in the frequency bands are installed in cavities different from each other.

Referring to FIG. 1, some of the first electronic components 16 a are mounted on the mounting substrate 11 for example via a ceramic substrate component 19 such as the LTCC (Low Temperature Co-fired Ceramic). In this practice, it is desirable to use a ceramic substrate component 19 which has a dielectric constant of about 5 to 40. In case the first electronic component 16 a is mounted on the mounting substrate 11 by way of heat-compression bonding of Au or Au—Sn alloy, for example using heat treatment at some 400 degrees centigrade, mounting is substantially impossible when the mounting substrate 11 is made of non-heat-resistant material.

In this case, as illustrated, by temporarily mounting the first electronic component 16 a on a substrate component 19 which has higher heat resistance than the mounting substrate 11 and which withstands heat treatment at some 400 degrees centigrade, and mounting the first electronic component 16 a on the mounting substrate 11 via this substrate component 19, it is possible to mount the first electronic component 16 a which requires heat-compression bonding on the mounting substrate 11 with low heat resistance.

The substrate component 19 may have a filtering feature in case it is necessary to remove an unwanted signal. The second electronic component 16 b may be also coupled to a mounting substrate 11 via the substrate component 19.

In case the mounting substrate 11 is made of ceramic which is the same as the member of the substrate component 19, the resulting propagation loss is higher and the antenna efficiency is lower, because ceramic has a higher dielectric constant than resin. Thus, the mounting substrate 11 uses a member which has a lower dielectric constant and lower heat resistance and, for a section where heat-compression bonding is required, uses a member which has a higher dielectric constant and higher heat resistance. While the mounting substrate 11 is composed of a single member, it may be composed of two or more members. For example, another member having a lower dielectric constant may be used between the antenna 17 and the shield layer 13 of the mounting substrate 11 in order to obtain better antenna efficiency.

The first electronic component 16 a or the second electronic component 16 b as a high-frequency device includes, but is not limited to, a power amplifier, a mixer, a multiplier, a frequency converter, a high-frequency oscillator, and a low-noise power amplifier.

Patch antennas (antennas) 17 comprising a predetermined conductor pattern are formed on the surface of the mounting substrate 11 opposite that on which the electronic components 16 are mounted. The plurality of patch antennas 17 are formed in an array so as to obtain good directivity. The patch antennas 17 include those transmitting/receiving a radio wave of 25 GHz and connected to the first electronic component 16 a via the transmission lines 12, and those transmitting/receiving a radio wave of 5 GHz and connected to the second electronic component 16 b via the transmission lines 12.

Instead of supporting multiple frequencies, the patch antennas 17 may be provided to support only one frequency and antennas supporting the other frequency may be provided separately from the electronic component module 10. Instead of an array of antennas, a single multi-band antenna capable of transmitting/receiving radio waves having a plurality of frequencies may be used. An antenna used is not limited to the patch antenna 17 according to this embodiment. Other forms of antennas including a reverse-F antenna and a slot antenna may be used.

On the mounting substrate 11, BGA (Ball Grid Array) terminals 18 each comprising a predetermined conductor pattern 18 a and a solder ball 18 b formed thereon, that is, a plurality of terminals are formed on the surface opposite that on which the patch antennas 17 are formed. The BGA terminals 18 are connected to the first electronic component 16 a and the second electronic component 16 b via the transmission lines 12. The electronic component module 10 is connected to peripherals via the BGA terminals 18. The terminals need not be BGA terminals 18 but various terminals having other shapes may be used.

As mentioned hereinabove, according to the electronic component module 10 of the embodiment, the first electronic components 16 a are installed in the first electromagnetically shielded cavity 14 a. The second electronic components 16 b whose operating frequency differs from that of the first electronic components 16 a are separately installed in the second electromagnetically shielded cavity 14 b. The electronic components are thus provided in modules so that the first and second electronic components 16 a, 16 b are shielded per frequency, thereby improving the isolation characteristic and obtaining a stable performance characteristic.

This provides an electronic component module which installs electronic components operating in frequency bands different from each other in a single package while preventing interference.

The electronic components 16 a, 16 b are mounted on the heat-resistant substrate component 19 by way of heat-compression bonding and the substrate component 19 is coupled to the mounting substrate 11 with a low dielectric constant. This makes it possible to mount the electronic components 16 a, 16 b requiring heat-compression bonding while suppressing propagation loss and improving antenna efficiency.

The cavity 14 is formed so as to suppress the unwanted resonance mode and the unwanted propagation mode in the operating frequency band of the electronic component 16 in the cavity 14. This obtains a good performance characteristic.

As understood from the foregoing description, the invention provides the following advantages.

First electronic and second electronic components are installed in electromagnetically shielded cavities separate from each other. The electronic components are thus provided in modules so that the electronic components are shielded per frequency, thereby improving the isolation characteristic and obtaining a stable performance characteristic.

This provides an electronic component module which installs electronic components operating in frequency bands different from each other in a single package while preventing interference.

The electronic components are mounted on a heat-resistant substrate component by way of heat-compression bonding and the substrate component is coupled to a mounting substrate with a low dielectric constant. This makes it possible to mount the electronic components requiring heat-compression bonding while suppressing propagation loss and improving antenna efficiency.

The cavity is formed so as to suppress the unwanted resonance mode and the unwanted propagation mode in the operating frequency band of the electronic component in the cavity. This obtains a good performance characteristic. 

1. An electronic component module comprising: a mounting substrate including a shield layer and transmission lines and on which at least a first cavity and at least a second cavity are formed; at least a first electronic component positioned in said first cavity and configured to be used in a first frequency band; at least a second electronic component positioned in said second cavity and configured to be used in a second frequency band; lid members equipped with a shielding feature configured to seal said first cavity and said second cavity; one or more antennas formed on a surface of said mounting substrate, said one or more antennas being connected to at least one of said first and second electronic components; and a plurality of terminals formed on said mounting substrate, said plurality of terminals connected to said first electronic component and said second electronic component via said transmission lines; wherein at least one of said first and second electronic components is mounted on said mounting substrate via a substrate component having a higher heat resistance than a heat resistance of said mounting substrate and said mounting substrate is composed of a member having a lower dielectric constant than a dielectric constant of said substrate component.
 2. The electronic component module according to claim 1, wherein said lid members include a metal or a nonmetal on which a metallic shield layer is formed.
 3. The electronic component module according to claim 1, wherein said mounting substrate member includes a resin and said substrate component includes a ceramic.
 4. The electronic component module according to claim 2, wherein said mounting substrate member includes a resin and said substrate component includes a ceramic.
 5. The electronic component module according to claim 1, wherein said shield layer is formed on an outer wall of said mounting substrate and a partition wall of said mounting substrate.
 6. The electronic component module according to claim 1, wherein said lid member and said shield layer being configured to electromagnetically shield said first cavity and said second cavity in all directions.
 7. The electronic component module according to claim 1, wherein said one or more antennas transmit or receive radio waves in at least one of said first frequency band and said second frequency band. 